Risk of depressive symptoms associated with impaired glucose metabolism, newly diagnosed diabetes, and previously diagnosed diabetes: a meta-analysis of prospective cohort studies

Patients with diabetes had a higher risk of developing depressive symptoms. Little is known about the risk of depressive symptoms associated with different glucose metabolism status. We performed a meta-analysis of prospective cohort studies to investigate the risk of depressive symptoms among individuals with impaired glucose metabolism (IGM), newly diagnosed diabetes (NDM), and previously diagnosed diabetes (PDM), compared with those with normal glucose metabolism (NGM), and further examined the influence of diabetes-related comorbidities on the association. PubMed and EMBASE were searched for relevant studies through 5 September 2015. The random-effects model was used to calculated overall relative risk (RR) and confidence interval (CI). Three separated meta-analyses were conducted by estimating the risk of depressive symptoms among people with IGM, NDM, and PDM, with NGM as a common reference category. Secondary analyses were conducted to examine whether adjustment for diabetes-related comorbidities affected the association. Five prospective cohort studies were included in the analyses, with a total of 18,051 participants involved. People with IGM (RR = 1.08, 95 % CI 0.84-1.38) and NDM (RR = 1.07, 95 % CI 0.74-1.55) were not associated with risk of developing depressive symptoms, whereas patients with PDM were associated with a modest increased risk of depressive symptoms (RR = 1.29, 95 % CI 1.03-1.63), after adjustment for demographic/socioeconomic factors. The risk of depressive symptoms associated with PDM was attenuated to be non-significant after pooling RRs that were adjusted for diabetes-related comorbidities. Our meta-analysis suggested people with PDM, but not IGM or NDM had an increased risk of developing depressive symptoms, and the risk was partially explained by diabetes-related comorbidities. Our findings indicated that routine diabetes care should put more emphasis on psychological problems of diabetic patients with complications.